The present invention relates to a stencil printer and more particularly to a stencil printer capable of making it needless for the operator of the printer to give consideration to the size or the orientation of papers.
A stencil printer extensively used today includes master making means for perforating, or cutting, a stencil in accordance with image data representative of a document image and thereby producing a master. The master is wrapped around a porous ink drum having ink feeding means arranged thereinside. A pressing member presses a paper or similar recording medium against the ink drum, so that a document image is printed on the paper via the master. The paper with the document image is driven out to a paper discharge tray included in a paper discharge section. Usually, the operator of this type of printer sets a document or documents in the same orientation as papers and then presses a perforation start key for making a master.
Generally, the outer periphery of the ink drum is made up of a porous portion where pores for passing irk therethrough are present and a non-porous portion where a damper for clamping the leading edge of the master is mounted. The porous portion has a length, as measured in the circumferential direction of the ink drum, matching with the maximum size of papers available with the printer, e.g., the maximum length of papers of size A3 prescribed by JIS (Japanese Industrial Standards). The master formed with a document image by the master making means is cut off in a size covering the entire porous portion, e.g., a length matching with size A3 without regard to the size of papers to be used and then wrapped around the ink drum. This, however, brings about the following problems.
Assume that the maximum paper size available with the printer is A3, but the operator desires printings of size A4, and that papers to be used are positioned vertically long. Then, almost one half of the resulting master is simply blank. Such a mater is removed from the ink drum and discarded when printing is to be executed with another document, aggravating the wasteful consumpt ion of a stencil. Further, ink fed from the inside of the ink drum is deposited over the entire area of the master. Therefore, ink deposited on the blank portions of the master is simply wasted together with the master.
In light of the above, Japanese Patent Laid-Open Publication No. 64-18683 proposes a stencil printer capable of varying the length of a master and the duration of contact of a pressing member in accordance with the kind (circumferential length) of an ink drum at the time of making a master and then producing printings with the master. This stencil printer, however, has a problem that it cannot save a stencil unless the ink drum is replaced every time the paper size is changed. In addition, the replacement of the ink drum is troublesome. Another problem is that the operator intending to set a document must check the size and orientation of papers and then set the document in the same orientation as the papers or set papers of the same size as the document, resulting in a troublesome procedure. Should the operator be inattentive, the document and papers might be different in orientation or size, resulting in defective printings.
Japanese Patent Laid-Open Publication No. 10-1254 teaches a stencil printer including a paper discharge tray on which an end fence movable forward and backward in a direction of paper discharge and a pair of side fences movable in the widthwise direction of a paper are mounted. In this kind of printer, paper size sensing means senses the size of papers stacked on a paper feed tray and allows each of the end fence and side fences to be moved to a particular position matching with the paper size. Although this scheme allows papers or printings to be neatly stacked on the paper discharge tray, it also forces the operator to check the orientation of the papers and then set a document in accordance with the orientation of the papers or set papers corresponding in size to the document.
Further, Japanese Patent Laid-Open Publication No. 5-306025 discloses a stencil printer including a plurality of paper feed trays each being loaded with papers of particular size. This allows a plurality of papers of different sizes to be stacked on the paper feed trays. However, the operator must confirm the orientation of papers and that of a document and must replace the papers if papers matching in size with the document are not available.
Moreover, assume that any one of the above conventional stencil printers prints a document image on papers by changing the magnification. Then, if papers having a size great enough to accommodate the resulting document image are not set, the printer cannot operate at all. Even when such papers matching in size with the document image are available in the printer, if they are different in orientation from the document, the operator must change the orientation of the papers or that of the document by troublesome operation.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 64-24783, 10-193767, and 11-228007.